Brush doffing with double cut-off plates



June 1957 R. M. SHELBURNE 3,323,

BRUSH DOFFING WITH DOUBLE CUT-OFF PLATES Filed May 28, 1965 2 Sheets-Sheet 1 'INVENTOR lb /MW;

( ATTORNEYS June 6, 1967 R. M. SHELBURNE 3,323,175

BRUSH DOFFING WITH DOUBLE CUTOF'E PLATES Filed May 28, 1965 2 Sheets-Sheet INVENTOR M ATTORNEQ? United States Patent 3,323,175 BRUSH DOFFING WITH DOUBLE CUT-OFF PLATES Richard M. Shelburne, Sherman, Tex., assignor to Hardwicke-Etter Company, Sherman, Tex., a corporation of Texas Filed May 28, 1965, Ser. No. 459,602 14 Claims. (Cl. 19-59) This invention relates to apparatus for removing fibers and lint from raw cotton, and in particular is concerned with an improved construction for a cotton gin stand or a cotton lint cleaner.

Cotton gin stands and lint cleaners are well known in the art. Such devices normally include a cylindrical saw which removes and straightens cotton fibers from a batch of raw cotton applied to a surface of the saw. The saw may act to separate cotton fibers from cotton seed and other foreign matter, or it may act to improve the condition of cotton fibers which have already been removed from the cotton seeds. Conventional apparatus also includes a cylindrical doffing brush having brush elements on its surface for removing cotton fibers that have been picked up by the saw. The dofiing brush is usually contained within a housing and in close proximity to the saw so that the fibers may be removed from the saw by rotating the brush in contact with the saw teeth. Fibers are picked up by the brush and conveyed to another part of the housing from which they are discharged for compacting or other processing steps. The brush is arranged to rotate on a central longitudinal axis of its cylinder, and rotation of the brush creates a draft within the housing which assists in the discharge of fibers from the surface of the brush. As the brush is rotated, an air stream is established from the point where the brush is loaded with fibers from the saw to the discharge point in the housing where the fibers are conveyed away from the brush and the housing.

Normally, a cut-off plate is mounted near the discharge opening of the housing and nearly in engagement with the brush elements so that no cotton fibers will be rotated past the discharge opening. However, in the prior art devices, a certain .portion of the cotton fibers and lint are drawn past the cut-off plate because of a difference in pressure existing in various par-ts of the d-olfing brush housing. The brush creates a draft by its rotation, and a higher pressure exists on the loaded side of the brush than on the unloaded side of the brush at any one time. The reason for this is that air is permitted to enter the housing in the areas where fibers are being removed and discharged from the loaded brush, and this air, together with the draft efiect created by the brush, results in a higher pressure in that part of the housing. From the point where the brush passes the usual cut-ofl? plate to the point where the unloaded brush again contacts the saw cylinder, there is a decrease in air pressure relative to the remainder of the housing. This relatively low pressure area is the result of an effective seal at the point of the cut-off plate coupled with the suction elfect created by the rotating brush as it rotates toward the saw and into the high pressure area of the housing.

Although the cut-off plate is designed to prevent passage of loose fibers and lint back onto the surface of the saw, it is well known that a certain percentage of the fibers and lint are drawn past the cut-off plate because of the difference in pressure on opposed sides of that plate. The difference in pressure is such that there is a suction created between the cut-off plate and the brush surface, and this suction pulls fibers past the cut-off plate and into the low pressure chamber of the housing. The passage of fibers past the normal discharge opening causes certain problems in operating gin stands and lint cleaner devices and affects the quality of cotton fiber being produced by such devices. An accumulation of fibers or lint in the low pressure chamber of the housing require-s periodic cleaning of the device and may result in loss of time or damage to the device. Furthermore, it has been found that a return of fibers onto the saw not only roughens the fibers, but may cause the fibers to be cut by the saw to shorter lengths. Rough fibers and shorter fibers lower the quality of the grade of cotton being pro duced and result in less money to the grower.

The present invention provides a construction to be used with a clotting 'brush which will assure better dis charge of all fibers and lint from the surface of the brush and which will prevent the passage of such fibers and lint into the low pressure chamber of the brush housing and ultimately onto the saw. It has been found that the use of a second cut-off plate spaced from the usual position of a first cut-off plate establishes a chamber which reduces the pressure differential existing across opposed surfaces of the first cut-01f plate. The second cut-off plate is positioned within the low pressure portion of the housing and downstream from the position of the first cut-off plate so as to establish two separate plates which the brush elements must pass in their movement from the discharge opening and back to the saw. The space be tween the :two cutoff plates is open to the atmosphere, and this arrangement produces a pressure within that chamber which is higher than the pressure normally found in the low pressure portion of the housing. As a result, suction is broken between the high pressure portion of the housing and the low pressure portion of the housing, and fibers are not drawn past the cut-off plates by the difference in pressure which normally exists. Although it is convenient to open the chamber between the cut-off plates to the atmosphere, it is also possible to introduce air at higher pressure into that space for the purpose of breaking the usual suction that exists between two parts of the housing.

Other features of this invention will become apparent in the more detailed discussion which follows. In the detailed discussion, reference will be made to the accompanying drawings in which:

FIGURE 1 is a vertical sectional view of a prior art gin stand having a single cut-off plate;

FIGURE 2 is a vertical sectional view of a gin stand incorporating the double cut-oif plates of this invention, and

FIGURE 3 is a vertical sectional View of a lint cleaner incorporating the double cut-off plates of this invention.

As shown in FIGURE 1, the usual gin stand includes a cylindrical saw 10 which rotates on its central longitudinal axis. A cylindrical doffing brush 12 is mounted with its longitudinal axis parallel to the axis of the saw, and the brush is rotated in close proximity to the saw so that the brush bristles 14 just touch the teeth 16 on the surface of the saw. The saw and the brush rotate as shown by the arrows so that fibers are picked up by the bristles 14 as the dofiing brush rotates past the surface of the saw. As viewed in FIGURE 1, the fibers are carried downwardly and around the lower portion of the brush for ultimate discharge from the surface of the dofiing brush. The doffing brush 12 is enclosed within a housing generally indicated at 18. The housing is designed to follow the contour ofthe brush in the area where the brush is loaded with cotton fibers, and a sufficient space is left between the housing and the brush for loose fibers and lint to be propelled through that part of the housing and to a discharge opening 20 located at a point in the housing remote from thecontact point between the brush and the saw.

In normal operation, the brush rot-ates as indicated, and this establishes an air stream around the surface of the brush which flows in the direction of rotation of the brush. An air inlet 22 is provided downstream from the loading point of the brush so that additional air may be drawn in the lower chamber 24 for the purpose of assisting in the removal and conveying of fibers away from the brush. A conventional cut-olf plate 26 separates the lower chamber 24 from an upper chamber 28 in the housing. The cut-off plate 26 is a flat plate mounted adjacent to the discharge opening 20 and which blocks the flow of fibers past the discharge opening and into the upper chamber 28. The cut-off plate normally extends toward the brush, and nearly touches the surface of the brush bristles 14 so as to establish the best possible seal.

The same action of the doffing brush which creates the air stream in the lower chamber 24 acts to draw air from the upper chamber 28. As a result, the air pressure in the lower chamber 24 is relatively higher than the air pressure existing in the upper chamber 28. This means that there is a pressure differential established on opposed sides of the cut-off plate 26, and the pressure differential is such that there is a tendency for fibers and lint to be drawn past the cut-off plate and into the upper chamber 28. In the past, there has been an attempt to prevent an accumulation of fibers in the upper chamber by providing an air intake at 30 to create a flow of air which will remove some of the lint and fibers from the upper chamber. The use of the air inlet 30 has been largely ineffective in that a certain portion of the fibers and lint that pass into that chamber find their way back to the surface of the saw where they are roughened and cut by the return trip across the saw teeth.

Looking to FIGURE 2, the present invention is shown as applied to a gin stand, and it can be seen that this device includes the usual saw 10 and dOffing brush 12 related in the manner described above for the prior art. The discharge opening 20 is connected with a discharge duct 32 which leads to a compacting device or to some other processing equipment. A first cut-off plate is shown at 26 in its usual position adjacent to the discharge opening and downstream from that opening when considering the direction of movement of the brush and the air stream established by that movement. In addition, a second cutoff plate 34 is shown as being placed in engagement with the brush surface, and this cut-off plate is spaced from the first cut-off plate so as to form a chamber 36 interposed between the lower chamber 24 and the upper chamber 28. The cut-off plates 26 and 34 are formed from sheet metal, or any other suitable material and are mounted for adjustment by means of the wing nut and bolt combinations 38. The bolts are placed through slots formed in the cut-ff plates and these slots are arranged to permit movement of the plate toward or away from the surface of the brush. Thus it is possible to adjust the spacing of the cut-off plates from the brush, and normally it is desirable that the plates clear the brush bristles by only to of an inch. It has been found that it is preferred to mount the first cut-01f plate 26 in closer proximity to the brush bristles 14 than the second cut-off plate 34. The staggered relationship of the cut-off plates to the brush bristles provides an effective seal at the location of the first cut-off plate while providing for passage of air from the intermediate chamber 36 to the upper chamber 28. The first cut-off plate 26 is preferably spaced to A3 of an inch from the brush bristles, and the second cut-off plate 34 is spaced from /8 to of an inch from the surface of the brush.

Since the chamber 36 is interposed for the purpose of breaking suction between the lower chamber 24 and the upper chamber 28, fewer fibers and particles of lint will be drawn past the first cut-ofi' plate than in prior devices. Preferably the chamber 36 is open to the atmosphere, and thus the pressure within that chamber is approximately atmospheric pressure. This pressure is higher than the a. pressure normally found in the upper chamber 28, and is sufficiently high to substantially prevent the passage of fibers and lint past the first cut-off plate. With the greater spacing of the second cut-off plate 34 from the bristles, as compared to the first cut-otf plate, air can flow from the chamber 36 into the upper chamber 28. The flow of air into chamber 28 aids in reducing the pressure in the upper chamber and also serves to remove the small number of fibers and particles that reach the upper chamber past the double cut-off plates.

FIGURE 3 shows an application of the present invention to a lint cleaner, and it can be seen that the saw 10 and dofling brush 12 rotate in directions opposite to that shown in the FIGURE 2 gin stand. Lint is removed from the saw atthe point of contact between the brush and the saw and is conveyed upwardly and around the surface of the doffing brush to a discharge duct 32. The cutoff plates 26 and 34 are arranged in the reverse order shown for FIGURE 2, so as to place the first cut-off plate immediately adjacent the downstream side of the discharge opening 20 and to place the second cut-off plate a sufficient distance further downstream to establish the intermediate chamber 36 which is open to the atmosphere.

. As in the case of a gin stand, the rotation of the brush about its central longitudinal axis creates an air stream which results in a positive pressure of air in the loading chamber 40, as compared to the opposed chamber 42, which is adjacent to the brush during its unloaded period of the cycle. The intermediate chamber 36 serves to prevent suction of lint past the first cut-off plate 26 and into the lower pressure chamber 42. It is contemplated that the intermediate chamber may be connected to a source of air pressure which is higher than atmospheric pressure and which will substantially reduce all suction between the higher pressure chamber and the lower pressure chamber. However, the preferred construction of opening the intermediate chamber to the atmosphere prevents substantiallyall lint and fibers from being drawn past the cut-off plates; and furthermore, the second cut-off plate can be easily mounted on existing structures for gin stands and lint cleaners without costly modification of such devices.

Although this invention has been described with reference to a single embodiment for gin stands and lint cleaners, variations will become apparent to those skilled in the art, and such variations are within the scope of this invention as claimed below. i

What is claimed is:

1. An apparatus for brushing and discharging fibers from a saw cylinder and including a doffing brush for removing the fibers from the saw cylinder and housing surrounding said doffing brush, the improvement comprising:

means defining a discharge opening in a wall of said housing remote from the point where said dofling brush removes fibers from said saw,

an air inlet into said housing for establishing an airstream from a point of loading said dofiing brush with fibers to the point of discharging fibers from the brush, whereby fibers will be removed from the brush and carried through the discharge opening with the assistance of the air stream,

a first cut-off plate downstream of said discharge opening for preventing passage of fibers carried by the airstream past said discharge opening,

a second cut-01f plate spaced further downstream from said first cut-off plate for establishing an air chamber between saidfirst and second cut-0E plates, said air chamber functioning to prevent suction of fibers past said first cut-01f plate.

2. The improvement of claim 1 wherein said air cham ber is in communication with atmospheric air pressure.

3. An apparatus for removing and discharging fibers from a saw cylinder and including a brush for removing the fibers from the saw and a housing surrounding said brush, the improvement comprising:

first means defining a first chamber in said housing for receiving and discharging fibers from the housing, said first chamber having air inlet means for establishing a positive pressure airstream which assists in removing fibers from said brush, and a discharge opening in a wall of said housing for discharging fibers from said housing,

second means definirv a second chamber in said housing, for containing air at a pressure lower than the pressure of air in said first chamber, and

said first and second means cooperating to define a third chamber interposed between said first and secnd chambers for preventing suction of fibers from said higher pressure first chamber into said lower pressure second chamber.

4. The improvement of claim 3 wherein said third chamber is in communication with atmospheric air pressure.

5. In a lint cotton cleaner apparatus:

a dofiing brush for removing lint cotton,

a housing surrounding said doifing brush for controlling the discharge of lint cotton from the cleaner apparatus,

means defining a discharge opening in a wall of said housing for discharging lint cotton from said doffing brush,

a cut-off plate between said housing and said dofiing brush for directing cotton lint through the discharge opening, and

suction breaking means adjacent to said cut-oif plate for preventing the suction of cotton lint past the cut-off plate and away from the discharge opening.

6. The apparatus of claim 5 wherein said suction breaking means comprises a second cut-off plate to form an air chamber adjacent said cut-cit plate and containing air at a sufficiently high pressure to break the suction of lint past the cut-oil? plate.

7. The apparatus of claim 6 wherein said air chamber is in communication with atmospheric air pressure.

8. The apparatus of claim 5 wherein said suction breaking means comprises a second cut-off plate spaced from said first cut-off plate to form a chamber adjacent said first named cut-ofi plate, whereby said chamber contains air at sutficient pressure to break the suction of lint past the first named cut-01f plate.

9, The apparatus of claim 8 wherein said first and second cut-off plates are mounted with thir respective edges in close proximity to the surface of said brush and with said first cut-off plate being mounted closer to the brush than said second cut-off plate.

10. In a cotton gin stand apparatus:

a dofiing brush for removing cotton fibers,

a housing surrounding said doffing brush for Cont-rolling the discharge of cotton fibers from the gin stand apparatus,

means defining a discharge opening in a wall of said housing for discharging cotton fibers from said doffing brush,

a cut-01f plate between said housing and said doifing brush for directing cotton fibers through the discharge opening, and

suction breaking means adjacent to said cut-of plate for preventing the suction of cotton fibers past the cut-ofi? plate and away from the discharge opening.

11. The apparatus of claim 10 wherein said suction breaking means comprises a second cut-01f plate to form an air chamber adjacent said cut-01f plate and containing air at a sufficiently high pressure to break the suction of fibers past the cut-off plate.

12. The apparatus of claim 11 wherein said air chamber is in communication with atmospheric air pressure. 13. The apparatus of claim 10 wherein said suction breaking means comprises a second cut-off plate spaced from said first cut-oft plate to form a chamber adjacent said first named cut-01f plate, whereby said chamber contains air at sufficient pressure to break the suction of fibers past the first named cut-off plat 14-. The apparatus of claim 13 wherein said first and second cut-off plates are mounted With their respective edges in close proximity to the surface of said brush and with said first cut-otf plate being mounted closer to the brush than said second cut-off plate.

References Cited UNITED STATES PATENTS 2,948,022 8/1960 Day 19-203 2,949,644 8/1960 Deems et a1. 1958 3,014,247 12/1961 Salmon 19-202 3,024,499 3/1962 Brooks 19-203 ROBERT R. MACKEY, Acting Primary Examiner. I. C. WADDEY, Assistant Examiner, 

1. AN APPARATUS FOR BRUSHING AND DISCHARGING FIBERS FROM A SAW CYLINDER AND INCLUDING A DOFFING BRUSH FOR REMOVING THE FIBERS FROM THE SAW CYLINDER AND HOUSING SURROUNDING SAID DOFFING BRUSH, THE IMPROVEMENT COMPRISING: MEANS DEFINING A DISCHARGE OPENING IN A WALL OF SAID HOUSING REMOTE FROM THE POINT WHERE SAID DOFFING BRUSH REMOVES FIBERS FROM SAID SAW, AN AIR INLET INTO SAID HOUSING FOR ESTABLISHING AN AIRSTREAM FROM A POINT OF LOADING SAID DOFFING BRUSH WITH FIBERS TO THE POINT OF DISCHARGING FIBERS FROM THE BRUSH, WHEREBY FIBERS WILL BE REMOVED FROM THE BRUSH AND CARRIED THROUGH THE DISCHARGE OPENING WITH THE ASSISTANCE OF THE AIR STREAM, A FIRST CUT-OFF PLATE DOWNSTREAM OF SAID DISCHARGE OPENING FOR PREVENTING PASSAGE OF FIBERS CARRIED BY THE AIRSTREAM PAST SAID DISCHARGE OPENING, A SECOND CUT-OFF PLATE SPACED FURTHER DOWNSTREAM FROM SAID FIRST CUT-OFF PLATE FOR ESTABLISHING AN AIR CHAMBER BETWEEN SAID FIRST AND SECOND CUT-OFF PLATES, SAID AIR CHAMBER FUNCTIONING TO PREVENT SUCTION OF FIBERS PAST SAID FIRST CUT-OFF PLATE. 